sudo iotop  won't work

$ sudo iotop -o
[sudo] password for emacs: 
Could not run iotop as some of the requirements are not met:
- Linux >= 2.6.20 with
  - I/O accounting support (CONFIG_TASKSTATS, CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING)


same things that it needs, also powertop needs(guessing) to display some statics like:
Summary: -nan wakeups/second,  -nan GPU ops/seconds, -nan VFS ops/sec and -0.0%

ok, for iotop to work (but not powertop wakeups/second and others seen above):
these two must also be enabled:

[*]   Enable extended accounting over taskstats
[*]     Enable per-task storage I/O accounting

so those are in addition to the usual(with which iotop didn't work):

    Cputime accounting (Simple tick based cputime accounting)  --->
[*] BSD Process Accounting
[*]   BSD Process Accounting version 3 file format
-*- Export task/process statistics through netlink
-*-   Enable per-task delay accounting


so powertop.... still needs other stuff to show those wakeups/second and stuff right
